Results of international standard problem No. 36 severe fuel damage experiment of a VVER fuel bundle
- Gesellschaft fuer Anlagen-und Reaktorsicherheit, Koeln (Germany)
- Nuclear Safety Institute of Russian Research Center, Moscow (Russian Federation)
- Ruhr-Univ. of Bochum (Germany); and others
International Standard Problems (ISP) organized by the OECD are defined as comparative exercises in which predictions with different computer codes for a given physical problem are compared with each other and with a carefully controlled experimental study. The main goal of ISP is to increase confidence in the validity and accuracy of analytical tools used in assessing the safety of nuclear installations. In addition, it enables the code user to gain experience and to improve his competence. This paper presents the results and assessment of ISP No. 36, which deals with the early core degradation phase during an unmitigated severe LWR accident in a Russian type VVER. Representatives of 17 organizations participated in the ISP using the codes ATHLET-CD, ICARE2, KESS-III, MELCOR, SCDAP/RELAP5 and RAPTA. Some participants performed several calculations with different codes. As experimental basis the severe fuel damage experiment CORA-W2 was selected. The main phenomena investigated are thermal behavior of fuel rods, onset of temperature escalation, material behavior and hydrogen generation. In general, the calculations give the right tendency of the experimental results for the thermal behavior, the hydrogen generation and, partly, for the material behavior. However, some calculations deviate in important quantities - e.g. some material behavior data - showing remarkable discrepancies between each other and from the experiments. The temperature history of the bundle up to the beginning of significant oxidation was calculated quite well. Deviations seem to be related to the overall heat balance. Since the material behavior of the bundle is to a great extent influenced by the cladding failure criteria a more realistic cladding failure model should be developed at least for the detailed, mechanistic codes. Regarding the material behavior and flow blockage some models for the material interaction as well as for relocation and refreezing requires further improvement.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Systems Technology; American Nuclear Society (ANS), La Grange Park, IL (United States); American Institute of Chemical Engineers, New York, NY (United States); American Society of Mechanical Engineers (ASME), New York, NY (United States); Canadian Nuclear Society, Toronto, ON (Canada); European Nuclear Society (ENS), Bern (Switzerland); Atomic Energy Society of Japan, Tokyo (Japan); Japan Society of Multiphase Flow, Kyoto (Japan)
- OSTI ID:
- 115065
- Report Number(s):
- NUREG/CP-0142-Vol.3; CONF-950904-Vol.3; ON: TI95017079; CNN: Contract RS 871 A; TRN: 95:022965
- Resource Relation:
- Conference: 7. international topical meeting on nuclear reactor thermal-hydraulics (Nureth-7), Saratoga Springs, NY (United States), 10-15 Sep 1995; Other Information: PBD: Sep 1995; Related Information: Is Part Of Proceedings of the 7th International Meeting on Nuclear Reactor Thermal-Hydraulics NURETH-7, Volume 3, Sessions 12-16; Block, R.C.; Feiner, F. [comps.] [American Nuclear Society, La Grange Park, IL (United States)]; PB: 1001 p.
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 NUCLEAR POWER REACTORS AND ASSOCIATED PLANTS
42 ENGINEERING NOT INCLUDED IN OTHER CATEGORIES
WWER TYPE REACTORS
SAFETY ANALYSIS
FUEL ELEMENT FAILURE
REACTOR ACCIDENTS
A CODES
I CODES
K CODES
M CODES
S CODES
R CODES
REACTOR SAFETY
HYDRAULICS
FUEL-COOLANT INTERACTIONS
EXPERIMENTAL DATA
COMPUTER CALCULATIONS
DIAGRAMS